Medical procedures have advanced to stages where less invasive or minimally invasive surgeries, diagnostic procedures and exploratory procedures have become desired and demanded by patients, physicians, and various medical industry administrators. To meet these demands, improved medical devices and instrumentation have been developed, such as cannula or micro-cannula, medical introducers, vacuum assisted biopsy apparatus, and other endoscopic related devices.
In the field of tissue biopsy, minimally invasive biopsy devices have been developed that require only a single insertion point into a patient's body to remove one or more tissue samples. One such biopsy device incorporates a “tube-within-a-tube” design that includes an outer piercing needle having a sharpened distal end and a lateral opening that defines a tissue receiving port. An inner cutting member is slidingly received within the outer piercing needle, which serves to excise tissue that has prolapsed into the tissue receiving port. A vacuum is used to draw the excised tissue into the tissue receiving port and aspirates the excised tissue from the biopsy site once severed.
Exemplary “tube-within-a-tube” biopsy devices are disclosed in U.S. Pat. Nos. 6,638,235 and 6,744,824, which are owned by the assignee of the present invention. Among other features, the exemplary biopsy devices can be used in conjunction with Magnetic Resonance Imaging (MRI). This compatibility is due to the fact that many of the components of the biopsy devices are made of materials that do not interfere with operation of MRI apparatus or are otherwise compatible therewith. It is desirable to perform biopsies in conjunction with MRI because it is a non-invasive visualization modality capable of defining the margins of a tumor.
Some biopsy devices may incorporate an introducer having an introducer cannula that may be placed over the biopsy needle extending from about the biopsy location to a location outside the patient. This introducer may remain in place after a biopsy is taken to permit the biopsy needle to be removed and a marker deployment device to be inserted within the introducer cannula in order to permit a marker to be positioned within the biopsy site. However, with differing sizes of outer cannula for biopsy needles and marker deployment devices, undesirable amounts of leakage between the outer cannula and the biopsy needle and/or marker deployment device may exist.
Additionally, biopsy needles and introducers are available in differing lengths, which demands that marker deployment devices be capable of sliding within the introducer a predetermined length for proper marker deployment. While a removable annular spacer positioned between the introducer hub and the marker deployment device may permit the marker deployment device to be inserted to a predetermined depth, interposing the marker deployment device within an annular spacer may increase the risk of contamination. Additionally, a spacer interposed between the introducer hub and the marker deployment device may not secure the introducer hub to the marker deployment device, thereby requiring a user to simultaneously deploy a marker while ensuring that the marker deployment device is properly positioned axially with respect to the desired marker deployment location.
While the exemplary MRI compatible biopsy devices have proven effective in operation, in some procedures it may be desirable to temporarily latch a biopsy device or marker deployment device to an introducer. A favorable introducer may also reduce leakage through the introducer cannula and provide for adjustability for the insertion depth of the marker deployment device.